Tube coating apparatus



Aug. 25, 1959 J. F. BARN ES ETAL 2,900,881

TUBE COATING APPARATUS Filed March 23. 1956 IN VEN TORS ATTORNEYS.

United States Patent 2,900,881 TUBE COATING APPARATUS James F. Barnes, Van Nuys, and Herman I. Silversher,

Los Angeles, Calif, assignors to Foil Process Corporation, Van Nuys, Calif., a corporation of California Application March 23, 1956, Serial No. 573,565

Claims. (Cl. 93-80) This invention relates to a tube coating apparatus, and more specifically to an apparatus for applying lubricative or protective materials upon the inner surfaces of tubes during their fabrication by tube winding machines.

In order to reduce friction during the spiral winding of paper or other materials upon the mandrels of tube Winding machines, efforts have been made to apply lubricants directly upon the strips or webs as they are being spirally wound. For this purpose, the hollow mandrels of such machines have been connected to lubricant reservoirs so that lubricant may pass through the mandrels and be applied directly upon the webs through mandrel slots or openings. Similar methods have been employed to coat the inner surfaces of the spirally wound tubes with protective or sealing materials.

In practice, however, it is found that such coating techniques are generally unsatisfactory. For one thing, the direct flow of fluid upon the webs often produces uneven or irregular coatings upon the inner surfaces of the tubes. If porous or absorbent materials are being spirally wound upon the machine, the fluid may penetrate certain portions of the webs passing directly over the ports while other portions of those webs receive insuflicient amounts of the coating fluid. In some instances, the localized penetration may become excessive, thereby weakening the tubes or otherwise impairing the quality of the finished product. Further, since a certain amount of fluid invariably remains within the hollow mandrels even after the reservoir passages have been closed, temporary shutdown or speed reduction of the machines may result in saturation of portions of the webs and may prevent or interfere with the continuation of winding operations.

Therefore, one of the main objects of the present invention is to provide coating means for tube winding machines which overcome the aforementioned defects and disadvantages of present structures. Another object is to provide means for insuring an even distribution of protective or lubricative materials upon the inner surfaces of tubes as they are being formed upon the mandrels of tube winding machines. A further object is to provide fluid retaining means for wiping the inner surfaces of tubes with fluid coating materials while those tubes are being spirally wound, the means also being adapted to retain fluid in order to prevent excessive fluid distribution when winding speeds are reduced.

Other objects will appear from the specification and drawings, in which Figure 1 is a broken perspective view of a tube winding machine equipped with the tube coating structure of the present invention; Figure 2 is a broken transverse cross sectional view taken along line 22 of Figure 1; Figure 3 is an enlarged broken cross sectional view showing a structural variation of the form of the invention represented in Figures 1 and 2; Figure 4 is a broken perspective view showing structural details of a second variation of the first form of the invention; and Figure 5 is a broken longitudinal cross sectional view representing another form of the invention.

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Referring to the drawings, Figure 1 shows a stationary mandrel 10 rigidly supported at one end by standard 11 of a tube Winding machine. On opposite sides of cylindrical mandrel 10 are vertical cylinders or rollers 12 which are journaled in frames 13 provided by the winding machine. An endless tube winding belt 14 is entrained about the rollers, and has a portion thereof looped or twisted about mandrel 10. Since the structure so far described is entirely conventional and well known in the art, a more detailed presentation is believed unnecessary herein.

As shown in Figure 1, mandrel 10 is provided with a plurality of longitudinal grooves or channels 15 along the outer periphery thereof. While three channels are shown in Figure 2, it will be understood that a larger or smaller number may be provided depending upon the size of the channels, the dimensions of the mandrel, and the character of the material to be wound thereon. From Figure 2 it will be seen that each of the channels are in communication with a vertical passage 16 in the solid end portion of the mandrel adjacent standard 11, by means of separate radial passages 17. Passage 16 may be threaded to receive a fluid flow conduit .18 extending be tween the mandrel and a suitable tank or reservoir 19. Conduit 18 is preferably provided with a valve 20 for regulating the flow of fluid from reservoir 19. While a gravity system for feeding fluid to the mandrel is shown in the drawing, it will be understood that mechanical means such as a pump may be used to create fluid pressure.

Wicks composed of a resilient absorbent material (such as felt) are carried within the channels 15 of mandrel 10. As illustrated in Figures 1 and 2, wicks 21 are elongated and have a generally rectangular cross section. Each of the wicks 21 extends the length of a channel 15 and is snugly held within its respective channel so that its outermost surface is co-extensive with the periphery of the mandrel. Preferably, the bottom of each channel has reduced lateral dimensions to provide a fluid flow passage 22 in communication with one of the radial passages 17. Consequently, when valve 20 is opened, absorbent wicks 21 will become saturated with tube coating fluid supplied from the reservoir and flowing along passages 22.

Figure 3 illustrates a variation of the wick and wicksupporting structure shown in Figures 1 and 2. In Figure 3, the wicks 23 each have a pair of longitudinal recesses 24 adjacent the bottom wall of each of the grooves 15. The arcuate recesses 24 provide relatively large surface areas for fluid penetration into the wicks and, in combination with the lower walls of grooves 15, provide longitudinal flow passages for the distribution of fluid to the wicks. The fluid then passes from the wicks to the wickcontacting inner surface of tube 25, as will be explained shortly.

Figure 4 shows another structural modification of the wick and wick support. The elongated channel insert member 26 has a generally rectangular cross section, and is adapted to be received Within a longitudinal channel provided by the mandrel of a tube Winding machine. Screws (not shown) or other suitable securing means may be used to mount the channel member within the mandrel recess. A plurality of wick elements 27 are carried by each of the hollow channel members, and project through rectangular openings 28 along the outer surfaces 29 of those members. When the channel members are properly mounted within the mandrel recesses, the outer surfaces 29 of the members and the exposed surfaces of the cubelike wicks are co-extensive with the periphery of mandrel 10. It will be noted that members 26 have longitudinally extending chambers 30 of substantially greater lateral dimension than wicks 2 7. As a result, fluid from reservoir 1 9 may throughchambers or passages 30 and circulate about the wick elem'ents.

When the tube winding machine is in operation, endless belt 14f rotated by power-driven rollers 12. Webbing 251 s fed upon maridrel TIO'in the e'ntio'nal triann ejr aridii i spiralil y wound' upon'jthe stat onaryi mandrel to form aftu b e. Tlfliefiuid satulrated"wieksjprovided by the. and rel'wipe agai'ristthe'innef surface of the" rotating tube andlevenlyldistribute fa thin film of 'fluid upon that guinea. T he' 'par'ticular' fluiduse d' for' any given tube fjinaifi bperatien depends; upo the purpose which the flu is Ltof'ServeJand the nature of the material being i d l Pfml. h m hd d I 1 fi f f th f ip or bsb ii w i 1 on the mandrel are jforrnedof pa er ofother porousjfnaterial, a j'wax 'such'las liquid fiin' y'beus Suchwaxesfactnofonly as reg 'ging fni' n between the mandrel th l ube, sma orr t r u j' s \iy iaterpioof coatingrn'a terial forthe' inner surface of the tube.

fSince'the wicks run'longitudinally alongthe mandrel, thet'rotating tube beingformed thereon iscontinu'ously wip'edfby the'fluid'retaining wicks. If, for any reason, the speedof thewiriding operationfmust be reduced, the absorbentwicksi will tend to retain fluidand prevent the distribution'of excess a'fnounts of fluid upon the inner surfaceof the tube, v p I V Where the material-being wound upon the machine is metal 'foil, it is evident that the metal-to-metahcoritact results in considerable frictional resistance betweenthe tube and mandrel. ""Since'the metal-foil is 'relatively'nonabsorbent; 'an" oil such asa "light hyd'rooarbon'oilmay provide a suitable anti-friction or release agent. Asthe spirally wou'ndfoil tubetwists upon the mandrel, the longitudinally extending Wi'cks'distribu'te an even filmof oil over the entire inner surface of the tube.

Figure represents another embodiment of the present invention which diflersfrom the form shown in Figures 1 and 2 onlyiin the manner by which fluid is conveyedto the wi'cks. "Hollow maridrel'Sl is identical to the mandrel already described, and'has a plurality of longitudinal grooves 32 along its periphery which are adapted'to tightly receive wicks 33. Fluid reservoir conduit 34 is threadedly received, by the mandrel, and communicates with a vertical bore 35 extending from the wall of mandrelj 31 ,intojan'inner plug 36' securely mounted within horizontal mandrel bore 37. A short flowlpassage 38 communicates with both the vertical bore 35 andthe larger horizontal bore 37 so that fluid may flow from the reservoir into the h o'llow mandrel.

Atthe opposite unsupported end of the mandrel is'a plug or cap' 39 which may bewelded or otherwise secured to the mandrel and which tightly seals mandrel bore 37. A plurality oi radial flow passages 40 extend between the central'bore 37 of the mandrel and wick elements 33. ns'equently, when horizontal "bore 37 is filled with coatingfflujdduiring' operation of the tubewinding niachine, the fluid will flow outwardly 'th'rough'passages 40 and saturate wicks 33. Preferably, passages40 are more clbselyspaced near thedistal end portionofthe'mandrel top'rovide' proper fluid distribution upon thecompletely formed tube "4l 'passing from thatend of the mandrel.

"While wick 33 is shown as a solid elongated wick completely filling mandrel channel 32, it is apparent that radial passages 40 may communicate with longitudinal passagessimilar to those shown in Figures 2-4. In other words, the mandrel may be provided with a reduced channel portion similar to that shown at 22 (Figure 2) or the wick itself may be provided with longitudinal flow passages similar to passages 24 (Figure 3). Furthermore, longitudinal channel '32 may be equipped with a channel member, such as channel member 26 (Figure 4), the radial passages 40 being constructed and arthat member.

While we have disclosed several embodiments and variations of the present invention in considerable detail for purposes ofi illustration, it will be understood by those skilled in the art 'that'n'rany of these details may be varied without departing from the spirit and scope of this invention.

-We claiin: n

1;"Iri-a tube windingmachine having a stationary mandrel provided withatleast'one longitudinal -groove*al6ng the outer;;periphery thereof, a resilient fluid absorbent Wick mounted said groove and 'having aburved outer surface flush withthe curvedperipheral surface of said mandrel, and fluid passage means including a bore extending longitudinally through said mandrel and communicating with said yvick along substantially the entire lengtlr the r'eof r rsuppi n tube coating fluid to" 'said wick, whereby, upon'operation of said tube windingniaohine said tubecoa'ting'material is' wiped from said'wick upon the inner surface of'a tube being Wound ii'pbn said :m andrel. V p

2.; The structure of claim 1 in which said passageni'eans including a 'pl'uri'alityof radial passages extending between saidjbore iand -s'aid 'wick, and a fluid 'reservoirequip ed with -a fluid flow conduit: in communication 'with"s'aid bore for supplying tubecoatingfluidto said 3 In a "tubewinding machine, a stationary cylindrical mandrelhaving a. plurality 'of elongatedlpei'ipheral cha nnels extending: substantially theen'tire length offi id mandrel, a plurality ofresilient fluid abs'o'rbent wicks mountedwithin said channels, 'said Wicks'having curved outer sur face-s flush the curved outer peripliery of a maadrshwd i Passage l an in i d n at 5s one longitudinal passage extending through substantially the lentire flength of said man'drel and communicating with said wicks for carrying't'ubefcoating fluid thereto, whereby, upon operation of said tube'winding 'macliiue, s'aid tube boating material is 'wip'ed 'rrom' sa'id wicjks upon the inner surface of a tube being formed upon s aid re -W. v hflfIhefstructure of'claim 3 in which each or an extends the 'leng'thliof one of said 'chan nels, said longp assage comprising a longitudinal recess extending alongthe lower surface of each channel adjacent the bottonithe'reof for carrying and distributing tube'coating flui qS jW k v t. i a 5 l 'l"he stru ctur 'ofclaim 3 in which an elonated eh'anneli member is-mounted within each of the channels of said mandrel, said longitudinalpassage comprising a longitlndinallyextending chamber providedby each channel In her, saidlchannelinernberseach being pt'ed igrs wet be seat n flu d t n a d h n b peni s-al ae h a Wa th e d Wicks 'b weip wi hiqi 'I d page SIi fi n longitudinally extending 'chambers thereof and projecting upwardly through said openings for distributing fluid upon a tube being foirned upon said mandrel. 

